Cigarette paper



CIGARETTE PAPER EdgarH. Harwood, Winston-Salem, N.C., assignor to R. J.Reynolds Tobacco Company, Winston-Salem, N.C., a corporation of NewJersey No Drawing. Application June 17, 1957 Serial No. 666,215

4 Claims. (Cl. 131-15) This invention relates to an improved cigarettepaper and, more particularly, pertains to an additive therefor whichgreatly improves the smoking and burning properties thereof.

Cigarette paper as now produced normally comprises essentially acellulosic sheet having various additives incorporated therein. Theseadditives may be used to add weight, control porosity, influence ashformation, regulate burning properties, provide opacity, and the like.It is apparent that the specific additive and the quantity thereofemployed are largely determined by the desired qualities in thecigarette paper utilizing the same.

It is important in the manufacture of cigarettes that the cigaretteswill not have a tendency to stop burning during smoking by the averagesmoker. It has been found that the burning may be controlled orregulated by incorporating additives into the cigarette paper so thatthe cigarette will not stop burning under ordinary conditions. Alsoduring cigarette smoking it is important that the ash formed by thepaper be one which will form a cylindrical ash sheath and not one whichwill flake. A cigarette paper which flakes during smoking is veryundesirable, since the ash flakes drop from the cigarette as formed,which is a source of irritation to the smoker.

It is an object of this invention, therefore, to provide a noveladditive intended for incorporation in cigarette paper which willregulate the burning rate of the cigarette paper.

It is another object of this invention to provide an additive forcigarette paper which insures continuous ignition as well as evenburning of the cigarette paper.

It is a still further object of this invention to provide a noveladditive for incorporation in cigarette paper which upon combustion willrelease aroma and flavor enhancing compounds, thereby adding to theenjoyment of the smoker.

It is yet another object of this invention to provide an additive forincorporation in cigarette paper which may be processed so as to releasea number of specific desired aroma and flavor enhancing compounds.

It is a further object of this invention to provide additives forcigarette paper which are simple in composition and which are easily andreadily incorporated in the paper product.

The above and other objects of this invention will appear from thefollowing description and appended claims.

In accordance with the broad principles of the subject invention, acigarette paper is provided having incorporated therein a small amountof an additive which upon smoking of the cigarette with which it isutilized will release one or more organic flavoring acids having from 3to 8 carbon atoms. In addition, the cigarette paper additive uponburning of the paper in which incorporated will form an ash which is ofsubstantial strength so as to hold an exceptionally long length oftobacco ash without allowing the ash to break 01f or flake when utilizedin a tobacco product. In the course of forming the latter ash, thecigarette paper additive of this invention assures a deditive.

2,886,041 Patented May 12, 1959 sired rate of combustion of the paperand also assures a continuous even burning action. The additive isnonvolatile and is of good stability, so that the cigarette paper orcigarette is capable of being stored for extended periods of timewithoutdecomposition or other change in the ad- In accordance with thisinvention, the additive for the cigarette paper comprises a sodiumpotassium salt of a substituted malonic acid having the formula:

COOH

OOH

wherein R is an alkyl, alkenyl, aryl, aralkyl, or other hydrocarbongroup having from 1 to 6 carbon atoms, and

preferably 2 to 4 carbon atoms. As pointed out in U.S.

- of these substituted malonic acids are incorporated into a cigarettepaper, the same flavors and aromas are obtainable, presumably by virtueof a combustion reaction upon burning which involves the decarboxylationof the substituted malonic acid compound. It will be appreciated thatsince isovaleric and 3-methylvaleric acids impart especially desiredflavor and aroma to cigarette smoke, the substituent group or R in theabove structural formula is preferably either isopropyl or secondarybutyl so that the latter-mentioned acids may be liberated in the courseof smoking, as will be understood from a consideration of said PatentNo. 2,766,145. However, the R group may be methyl, ethyl, n-propyl,n-butyl, straight or branched chain pentyl or hexyl, aryl, cycloalkyl,or the corresponding unsaturated compounds, all as indicated in saidprior patent.

In order to provide for proper control of burning and ashing of thecigarette paper of this invention, the salts of the substituted malonicacids are the sodium and potassium salts either as a mixture of thedisoditun and dipotassium salts, a mixture of the monosodium andmonopotassium acid salts or the sodium potassium salts. The sodiumpotassium salts having the formula:

0 0 ONa are preferred. It has been found that both the sodium andpotassium are instrumental in preventing ready flaking of the paper ash,that the potassium functions to maintain burning, and the sodium isinstrumental .in promoting even burning.

The salts of the substituted malonic acids may be added to the cigarettepaper in amounts of from between .1 and 5 percent of the dry weight ofthe cigarette paper. The salt additive may be incorporated throughoutthe paper either at the time of paper manufacture or subsequent theretoby impregnating the paper with a solution of the salt and then dryingthe impregnated paper. The provided salts may be applied to the paper inaqueous solution, or may be dissolved in any other suitable solventwhich will leave no characteristic odor or taste and which is preferablyof a volatile nature. The latter solvents obviously should not reactwith the malonic acid salts. The molar ratio of sodium to potassium inthe additive is suitably about one to one in order to obtain the desiredresults. However, this ratio may be varied between about nine to one andone to nine.

A particularly suitable cigarette paper is prepared by impregnating asuitable paper with an aqueous solution of sodium potassium secondarybutyl malonate in amounts to provide a paper containing 2 percent byweight (dry basis) of the malonate. The paper is then dried and used inmaking a cigarette. Upon smoking, the burning and ashing characteristicsof the cigarette are satisfactory and the liberated 3-methylvaleric acidproduces a desired aroma upon burning.

The substituted malonic acids referred to herein are well known in theart and the sodium and potassium salts thereof may be prepared bytreating the acids with a sodium and/or potassium base, such as thehydroxide or carbonate, by well known methods. As is known, the sodiumpotassium salt may be prepared by treating the free acid with equivalentamounts of a mixture of the sodium and potassium bases.

It is obvious that many modifications of the above-described inventionmay be made which will still remain within the ambit of the inventiveconcept disclosed. It is intended, therefore, that this invention belimited only by the scope of the appended claims.

I claim:

1. A cigarette paper having added thereto sodium and potassium salts ofsubstituted malonic acid having the formula sodium potassium-substitutedmalonic acid having the formula wherein R is a hydrocarbon radicalhaving from 1 to 6 carbon atoms.

4. The paper recited in claim 3 wherein R is an alkyl group having from2 to 4 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS2,028,552 Low Jan. 21, 1936 2,766,145 Jones Oct. 9, 1956 2,766,150Teague Oct. 9, .1956

1. A CIGARETTE PAPER HAVING ADDED THERETO SODIUM AND POTASSIUM SALTS OFSUBSTITUTED MALONIC ACID HAVING THE FORMULA